The present invention relates to a scroll type compressor having a fixed scroll member and a movable scroll member which is adapted to make an orbital motion while being prevented from rotating on its axis by a rotation preventing mechanism whereby a compression chamber whose volume is variable is formed between the fixed scroll member and the movable scroll member.
In general, a scroll type compressor includes a fixed scroll member having a fixed end plate and a fixed scroll wall and a movable scroll member having a movable end plate and a movable scroll wall. The fixed and the movable scroll members are disposed in a housing with the scroll walls thereof engaged with each other. The movable scroll member orbits around the axis of the fixed scroll member and refrigerant gas taken into a compression chamber defined between the fixed and the movable scroll walls of the scroll members is compressed with a decrease in the volume of the compression chamber in accordance with the orbital motion of the movable scroll member.
The scroll type compressor has a rotation preventing mechanism that prevents the rotation of the movable scroll member and allows the movable scroll member to orbit around the axis of the fixed scroll member Japanese Patent Application Publication H7-167067 discloses a rotation preventing mechanism. The rotation preventing mechanism includes a plurality of movable pins provided on the end surface of the movable scroll member for orbiting in accordance with orbital motion of the movable scroll member and a plurality of fixed pins provided on the end surface of a casing forming a part of the fixed scroll member for contact engagement with the movable pins. When the movable scroll member orbits around the axis of the fixed scroll member, each movable pin of the movable scroll member orbits around its paired fixed pin of the fixed scroll member. Contact engagement of the paired movable and fixed pins allows the movable scroll member to make an orbiting motion while being prevented from rotating on its axis.
In the rotation preventing mechanism of the above Publication, the movable pins and the fixed pins are fixed to the end surface of the movable scroll member and the casing, respectively, by press fitting. A force acting on the movable scroll member for rotation on its axis is transmitted to each fixed pins due to the contact engagement thereof with its paired movable pin and further to the casing. With the fixed and the movable pins in contact engagement with each other, sliding contact arises in the movable pin and/or fixed pin and friction resistance due to the sliding contact arises therebetween. Accordingly, there has been problems that the power loss increases in the scroll type compressor and both movable and fixed pins are subject to wear.
The present invention is directed to providing a scroll type compressor that can reduce the friction resistance between the movable and the fixed pins and the wear of the pins.